Expansible mandrel including jacks, for driving tubes into the ground



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4 Sheets-She'et 1 TUBES INTO THE GROUND DRIVING EXPANSIBLE MA Feb. 3,

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DRIVING TUBES INTO THE GROUND"v 4 Sheets-Sheet 5 Filed may 14, 1954 Ey. a.

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Feb. 3, 1959 DRIVING TUBES INTO THE GROUND Filed May 14. 1954 4 Sheets-Sheet 4 United tat EXPANSIBLE MANDREL INCLUDING JACKS, FOR DRIVING TUBES INTO THE GROUND Edgard Pickman, Brussels, Belgium, assigner to Compagnie Internationale des Pieux Armes Frankignoul, Societe Anonyme, Liege, Belgium Application May 14, 1954, Serial No. 429,993

Claims priority, application France March 15, 1954 2 Claims. (Cl. 61-79) The invention relates to an expansible mandrel for driving tubes into the ground, especially thin tubes intended to be left in the ground and filled with concrete or like material, to form foundation piles.

Such expansible mandrels are known, and include a number of elongated segments which are movable radially with respect to each other. After the mandrel has been introduced into the tube to be driven, it is made to expand, that is to say, the segments thereof are moved radially outward, so as to press against the inner wall of the tube, and the latter is then driven into the ground by the blows of a hammer upon the upper end of the mandrel. All that need be done then is to contract the mandrel so that it may be withdrawn from the tube and engaged in another tube to be driven into the ground.

The invention relates to a mandrel of the described type in which the expansion is produced through means actuated by fluid under pressure, which are capable of bringing about the radial movement of the segments without the use of members which are movable longitudinally with respect to the said segments and which are thus subjected to detrimental stresses due to inertia. More particularly, the invention has for its object to provide an expansible mandrel of the described type, in which, however, the uid pressure actuated operating means act positively and directly upon all of their thrust points provided on the segments, and in which the said operating means are particularly sturdy. To this end, a mandrel embodying the invention has the expansion of the segments produced by fluid pressure operated jacks which are arranged at right angles to the segments, at the center of the cross sectional area of the latter, with at least two jacks being distributed over the length of each segment.

The Vcontraction of the segments may be effected by means of return springs, which, however, reduce the retracting force. According to the invention, contraction of the mandrel segments is preferably also effected by fluid pressure operated jacks, which makes it possible for the retracting forces to be varied, so as to suit various working conditions. If use is made of double-acting jacks, with each of the pistons being attached to a related segment, the same jacks may be used for expansion and contraction. However, separate sets of jacks may be used for the expansion and contraction, respectively.

The number of segments is preferably an even number, conveniently four, the jacks being arranged so that leach jack acts upon one pair of diametrally opposed segments.

According to one embodiment of the invention, all the jacks are supported by a central member of the mandrel having cylinders disposed at right angles to the axis thereof, there being arranged in each of the ysaid cylinders a pair of pistons acting upon a pair of diametrally opposed segments.

According to a preferred embodiment of the invention, the cylinder of each jack is secured to one segment,

While the piston thereof acts upon the diametrally op? 2,871,666 Patented Feb. 3, 1959 fice posed segment, the said piston being attached to the latter where it is desired to contract or bring together such segments.

Further features and advantages of the invention will appear from the following detailed description of illustrative embodiments thereof which is to be read with reference to the accompanying drawings wherein certain structural details, which are not essential for the clear understanding of the invention, have been omitted and in which:

Figure 1 is a central sectional view of a mandrel according to the invention, the mandrel being engaged in a corrugated tube and in an expanded position;

Figure 2 is a similar view of the mandrel in the contracted position, the sectional plane being shifted angularly by Figures 3 and 4 are sectional views taken on line III-Hl of Fig. 1 and line IV--IV of Fig. 2, respectively;

Figure 5 is a fragmentary, longitudinal sectional view of a modication of a detail of the construction;

Figure 6 is a sectional view taken on line VI-VI of Fig. 5;

Figures 7a and 7b show upper and lower portions of a central sectional view of a further way of carrying out the mandrel according to the invention, in the expanded position;

Figure 8 is a similar view of the lower portion of the mandrel in the contracted position;

Figures 9, 10 and 11 are respectively sectional views on a slightly enlarged scale, taken on line IX-IX, line X-X and offset line XI-XI of Figs. 7a and 7b;

Figures 12, 13 and 14 are sectional views on a slightly enlarged scale, taken on line XII-XII, line XIII-XIII and offset line XIVXIV of Fig. 8, respectively;

Figure 15 is a fragmentary longitudinal section of a further constructional modication of the mandrel, and

Figure 16 is a sectional view taken on line XVI-XVI of Fig. l5.

The drawings illustrate mandrels for driving cylindrical tubes, but it will -be seen that the mandrel may be conveniently made to be suitable for driving tapering tubes, or even tubes having a non circular cross section, with smooth or corrugated walls.

In the example of Figures 1-4, the mandrel includes four radially movable segments 1. To achieve this, the segments are for instance provided at their upper ends with flanges 2 by means of which the segments are connected to a percussion helmet 3 furnished with a percussion piece 4 made from wood or the like, intended to be subjected to the blows of a rammer. The segments 1 may be assembled with the helmet 3 by means of bolts 5 extending through the flanges 2 and a corresponding ange 6 of the helmet, the hole 7 in each r'lange 2 being in the form of a slot in order to allow for the radial movement of the segments while the shafts of the bolts are of such length as to have a certain play between the heads of the bolts and the ilange 2 after the nuts of the bolts have been tightened.

The radial movement of the segments 1 is eiected by hydraulic or air pressure operated jacks S, 9 mounted on a central structure extending along the whole length of the mandrel. In the example illustrated, the structure is comprised of spaced blocks 10, tubes 11 welded to the blocks, an upper end rod 12 secured to the helmet 3 and a base plate 13 on which the lower ends of the segments are adapted to rest.

ln each block 10 there are formed two cylinders 14, 15 extending at right angles to each other and spaced vertically, each cylinder having mounted therein two pistons 16, 17 withpiston rods 18, 19 extending therefrom to each cooperate with a segment 1. The piston rods 18, 19 may be secured to the segments by means of'serews 20.

Alternately, and as shown in Figs. -6, each piston rod may be provided with an enlarged head 21 engaging a slide 22 having a closed upper end and an open lower end so that the segment has freedom 'of movement with respect to the jacks in the vertical direction, with the result that the transmission of shocks from the segments to the central structure is avoided.

The jacks illustrated are double acting, the fluid under pressure being admitted to the central portion of each of cylinders 14, 15, through a pipe 23 and being admitted to the cylinders to act against the outer faces of the pistons 16, 17 through the pipes 24, 25. To cause the mandrel to expand, all that need be done is to build up the pressure in pipe 23 and to release the pressure through pipes 24 and 25, while, to cause the contraction of the mandrel, the pressure is built up in the pipes 24 and 25 and is released through pipe 23.

In Order to prevent slipping of the mandrel with respect to the corrugated tube 26 during driving, ribs 27 may be provided on the segments 1 for engagement with corrugations of the tube. The tube 26 may have its base sealed by a plate 28, or the tube may be left open, in which case it will conveniently extend downwardly for a certain length beyond the base 13 of the mandrel, and a compressed plug of concrete or like material may be formed in the extending portion of the tube to serve as a driving shoe and to secure a tight seal for the tube.

It will be understood that numerous constructional changes may be adopted in the above described apparatus, particularly with respect to the construction of the jacks, their relative arrangement with respect to each other, the connecting means between the pistons of the jacks and the segments of the mandrel, and so on. 1f the dimensions of the apparatus permit, more than two jacks may be arranged in the same horizontal plane in such a manner that their cylinders are in communication with a common central chamber which is connected to an operating fluid pipe. The contraction of the segments of the mandrel may also be eiected by return springs arranged between the segments and the central structure, in which case the jacks may be single-acting to eiect only the exr pansion of the segments, and their pistons need not be attached to the segments.

Figures 7a to `14 illustrate a very expedient and convenient construction of a mandrel according to the invention. This includes four segments 29 having their upper ends connected to each other, as are also the lower ends thereof, in such a manner as to allow for a limited radial movement of the segments. While other connections may be contemplated, the one which will be hereinafter described is simple and efficient. The upper ends of the segments are connected to an anvil 30 (Fig. 7a) and the lower ends thereof to an anvil 31 (Fig. 7b). Since the connections are similar, only the lower connection will be described in detail'.

The anvil member 31 has a projection 32 of cross form, which extends into the hollow interior of the mandrel. A pair of bosses 33 is welded to the inner surface of each segment 29, and the bosses 33 are arranged at the opposite sides of one of the arms of the crossshaped projection 32 and are attached thereto by means of pivot pins 34 held in bores in the bosses 33 and extending through a slot 35 in the corresponding arm of the projection 32, so as to permit radial movement of the corresponding segment 29. The pivot pins 34 are secured in position by means of set screws, such as the screw 36 which has been shown in Figure 11, and which is situated outside the plane of the sectional view of Figure 11V and is substantially tangential with respect to the corresponding pivot pin 34.

The striking forces are transmitted to the anvil member 30, from which they are conveyed to the segments 29 and from thence to the anvil member 31. The anvil member 30 is suspended, by a central link 37 and pivot pins 38, 39, from a base member 40 of a steam or other matters and provide ready access to the jacks.

rammer. Such suspension has a certain play 41 therein in order to permit angular shift of the axis of the mandrel with respect to the axis of the rammer and thus to avoid breakage of parts in the event the mandrel is deected accidentally while the tube is being driven.

The expansion of the segments 29 of the mandrel is effected by means of diametrally arranged jacks each acting upon a pair of diametrally opposed segments, whereby the number of jacks may be kept to a minimum. Two or more suitably spaced apart expansion jacks are provided for each pair of segments, the jacks associated with the various pairs of segments being spaced vertically apart with respect to each other. While the contraction of the mandrel may be effected by return springs, the apparatus embodying the invention may further have retraction jacks which are each arranged between a pair of diametrally opposite segments and are spaced apart vertically, both with respect to each other and with respect to the expansion jacks.

Each expansion jack includes a cylinder 42 welded between two ribs 43 of a segment, and a piston 44 adapted to thrust against an abutment 45 welded between the ribs 46 of the opposite segment, The uid under pressure is supplied to each set of jacks associated with the same pair of segments through a pipe 47, and the dischargeV of the fluid can occur through the same pipe 47 when the mandrel is contracted.

Each retraction jack includes a cylinder 48 welded between two ribs of a segment, preferably the segment opposite to the one carrying the cylinder 42, in order to better balance the assembly and to simplify and better distribute the layout of the fluid pipes. Each cylinder 48 has a piston 5t) therein provided with a piston rod 51 having an enlarged head 52 which engages in a vertical guide 53 welded between ribs 54 of the segment opposite the one carrying the cylinder 48. The iiuid under pressure is supplied to the set of contraction jacks associated with the same pair of segments through a pipe 55 and is also discharged therethrough when the mandrel is being expanded. Therefore, to move the segments in the one or the other direction, all that need be done is to shut off the fluid pressure in one of the sets of pipes and to build up the uid pressure in the other set of pipes.

The pipes 47 and 55 emerge from the segments laterally, adjacent the upper ends thereof, and the loss of strength due to the segment being perforated is compensated by a reinforcing member 56 welded onto the segment (Fig. 7a). The above arrangement avoids the complication resulting from extension of the pipes through the helmet 3, as in the case of Figures 1 and 2.

Assembling and disassem'bling the mandrel are Simple The jacks are mounted on the respective segments before the assembly thereof. The push pistons 44 being free or slidable with respect to the abutments 45, a longitudinal relative displacement of the oppositely arranged segments is all that is required in order to engage the head 52 of the piston rod 51 in the guide 53 or to disengage it therefrom. Assembling the segments by means of the anvil members 30 and 31 is also an easy matter.

As in the case of Figures 1-4, the segments 29 may be provided if desired, with outer ribs 27 for engaging corrugations of a corrugated tube. Likewise, the anvil 31 may rest upon a plate forming the base of the tube; or the tube may extend beyond the lower end of the segments and have its lower end lled with a compressed plug from concrete or the like, formed underneath the anvil 31. The plug may be formed in an extended, conveniently reinforced portion of the tube, as `described above, or in a short length of tube secured underneath the anvil member 31.

The segments of the mandrel in each of the various illustrative embodiments described above may 'be of one piece construction, or each segment can be made .in several sections arranged end to end and suitably as sem'bled together. With this arrangement, the mandrel may be comprised of a special head member and a special base member and of a number of intermediate, identical members, which makes it possible to vary the length of the mandrel at will.

Figures -16 show a way in which the various sections can 'be assembled together to form a segment. The segmental sections 29a, 29b are provided at their opposite ends with plates 57, 58, at right angles to the wall of the segment. It will be apparent that the plate 58 omitted from the upper end of the uppermost section, and the plate 57 is omitted from the lower end of the lowermost section. The plate may be welded to the segment, the contour of the plate being -determined by that portion of the cross sectional area of the mandrel, which is available when the latter in contracted. The adjacent plates 57, 58 are assembled by means of bolts or screws, for instance one screw 59 and two screws 69. The fluid supply pipes, such as the pipe 5S, are connected to registering openings 61 provided in the plates 57, 58, and the assembly may be made iluid tight by means of a sealing member 62.

It will 'be understood that various constructional changes may be made in the above described embodiments of the invention, without departing from the spirit or scope of the invention, except as defined in the appended claims.

I claim:

l. An expansible mandrel operable with driving means for driving tubes into the ground, comprising an even number of longitu-dinally extending segments having upper ends for receiving a driving force applied by the driving means, said segments being arranged in diametrically opposed pairs and movable radially with respect to each other, each of said segments having an arcuate member for application against the inner surface of the tube to be driven, fluid pressure operated jacks arranged at right angles to the longitudinal axes of the segments at the center of the cross-sectional area thereof for acting on the central portions of the associated arcuate members at least two jacks associated with each pair of diametrically opposed segments and distributed along the length of the latter with the jacks associated with different pairs of segments being spaced apart in the longitudinal direction of the latter, each of said jacks including a cylinder secured to the arcuate member of one of the related pair of segments and having an open inner end with a piston slidable in the cylinder, a thrust member on the arcuate member of the other of said related pair of segments which is diametrically opposed to said one segment on which the cylinder is secured and being located in alignment with said piston to receive the thrust of the latter when the piston is projected out of said open inner end of the related cylinder, means for supplying uid under pressure to the outer end of the cylinder of each jack adjacent the arcuate member to which said cylinder is secured so that the pistons of the jacks are projected out of the open inner ends of the related cylinders to eiect radially outward movement of the segments, and contraction means operatively connected to said segments and capable of causing radially inward movement of said segments upon the elimination of the Huid pressure acting in said jacks to cause said radially outward movement.

2. An expansible mandrel operable with driving means for driving tubes into the ground, comprising an even number of longitudinally extending segments arranged in diametrically opposed pairs, said segments being radially movable with respect to each other and having upper ends for receiving a driving force applied by the driving means, each of said segments having an arcuate member for application against the inner surface of the tube to be driven, lirst jacks operated by fluid under pressure and arranged at right angles to the longitudinal axes of the segments at the center of the cross-sectional area thereof for acting on the central portions of the associated arcuate members, at least two of said first jacks being distributed along the length of each segment, means for supplying uid under pressure to said lirst jacks in the direction to eect radially outward movement of said segments, second jacks operated by uid under pressure and arranged at right angles with respect-to, and secured to, said segments at the center of the cross-sectional area of said arcuate members for effecting radially inward movement of said segments, each of said second jacks including a cylinder secured to the arcuate member of a related segment and having an end wall with a central aperture at the inner end of the cylinder, a piston slidable in said cylinder and a piston rod extending from said piston through said central aperture, said piston rod having an enlarged head on the end thereof remote from the related piston, said arcuate member of the segment which is diametrically opposed to said related segment having a guide secured thereto and dening a longitudinal groove which `slidably receives said enlarged head and opens at one end, as well as radially inward, through a slot of reduced width receiving said piston rod, so that said guide and enlarged head provide an operative connection between said piston rod and said arcuate member of the segment which is diametrically opposed to said related segment, said second jacks cooperating with diiferent diametrically opposed pairs of segments being spaced apart in the longitudinal direction of the latter, and means opening into the cylinders of said second jacks adjacent the inner ends thereof for supplying uid under pressure to said cylinders of the second jacks to eiect radially inward movement of said segments upon the elimination of the iluid pressure acting in said rst jacks to cause said radially outward movement.

References Cited in the le of this patent UNITED STATES PATENTS 2,321,146 Jones June 8, 1943 2,437,043 Riemenschneider Mar. 2, 1948 2,625,015 Cobi Ian. 13, 1953 2,655,977 Hodgkins Oct. 20, 1953 2,684,577 Smith July 27, 1954 

